ANTARCTIC MICROBES COULD LIVE ON MARS

New Zealand and Canadian scientists have uncovered microbes in Antarctica that live in hostile conditions mirroring those on Mars.
The scientists discovered long-lived colonies of insecticidal fungi and a common species of Penicillium bacteria at two sites in Antarctica's Dry Valleys — so-called because they are ice-free — living three to eight centimetres beneath the surface.
They describe their findings in a paper in Icarus.

Professor William Mahaney, from York University in Canada, accompanied two New Zealand researchers on one of their field trips to the Antarctic a couple of years ago.

"He was desperate to get down there so we took him," said Dr Doug Sheppard of Geochemical Solutions in New Zealand, who was looking at the chemical conditions under which microbes try to survive in Antarctica.

"He's a specialist in particular types of glacial processes."

The group was investigating paleosols (ancient soils). By using a beryllium-10 isotope dating technique, they were able to focus on layers of soils that were 10 to 15 million years old. Then they dug holes in the ground and looked for microbes.

"There is a perception around that these soils don't contain any life, but that's not true. There is a limited range of bacteria and fungi," said Dr Sheppard. "But the population densities are quite low."

There is no such thing as a sterile place on Earth, he said: organisms live everywhere.

"Living is an interesting word actually — they are 'existing'. They are mostly dormant until conditions are right to get them going."
If there was some snowfall, for example, which melted to form liquid water, the organisms would be activated.

The salt concentration in the soil containing the microbes was 3,000 parts per million, which is extremely salty. The advantage of the salt is that it lowers the freezing point: frostbite, for example, would not occur until the temperature was down to minus 56 degrees.

Even apart from the salt, conditions where the microbes were found were particularly cold and dry. The mean annual temperature is between minus 30 and minus 35 degrees Celcius, and less than 10 mm of precipitation falls each year.

These very arid, cold soils formed under environmental conditions similar to those on Mars.

"There's not a lot of water on Mars, and what water there is will be at depths in the soils," explained Dr Sheppard.

"So the types of living conditions you have got in those soils are likely to be pretty similar to those we find in some parts of Antarctica."

New Zealand researcher, Dr Iain Campbell of Land and Soil Consultancy Services, and two planetary scientists from the University of Arizona also collaborated on the project.

In another discovery this week, US researchers report in Nature that they have found microbes able to produce energy from hydrogen in geothermal water 200 metres underground at Hot Springs in Idaho.

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